Sleep onset insomnia, daytime sleepiness and sleep duration in relationship to <i>Toxoplasma gondii</i> IgG seropositivity and serointensity

Abstract

<i>Toxoplasma gondii</i> (<i>T. gondii</i>) infects central nervous tissue and is kept in relative dormancy by a healthy immune system. Sleep disturbances have been found to precipitate mental illness, suicidal behavior and car accidents, which have been previously linked to <i>T. gondii</i> as well. We speculated that if sleep disruption, particularly insomnia, would mediate, at least partly, the link between <i>T. gondii</i> infection and related behavioral dysregulation, then we would be able to identify significant associations between sleep disruption and <i>T. gondii</i>. The mechanisms for such an association may involve dopamine (DA) production by <i>T. gondii</i>, or collateral effects of immune activation necessary to keep <i>T. gondii</i> in check. Sleep questionnaires from 2031 Old Order Amish were analyzed in relationship to <i>T. gondii</i>-IgG antibodies measured by enzyme-linked immunosorbent assay (ELISA). <i>Toxoplasma gondii</i> seropositivity and serointensity were not associated with any of the sleep latency variables or Epworth Sleepiness Scale (ESS). A secondary analysis identified, after adjustment for age group, a statistical trend toward shorter sleep duration in seropositive men (p = 0.07). In conclusion, it is unlikely that sleep disruption mediates links between <i>T. gondii</i> and mental illness or behavioral dysregulation. Trending gender differences in associations between <i>T. gondii</i> and shorter sleep need further investigation.